From the Guidelines
Metabolic alkalosis should be treated based on its underlying cause, with a focus on correcting the primary issue, and may involve the use of normal saline, potassium chloride, or specific medications like acetazolamide, as well as discontinuation of causative agents and management of underlying conditions. The causes of metabolic alkalosis can be diverse, including excessive vomiting, diuretic use, and certain endocrine disorders. Treatment options vary depending on whether the alkalosis is chloride-responsive or resistant. For chloride-responsive cases, which are common in scenarios such as vomiting or diuretic use, the administration of normal saline (0.9% NaCl) at a rate of 100-200 mL/hour is a primary approach, as it provides the necessary chloride ions to facilitate bicarbonate excretion [ 1 ]. Additionally, potassium chloride supplementation is often required to address accompanying hypokalemia, which can perpetuate the alkalosis.
Treatment Approaches
- For mild metabolic alkalosis, addressing the primary cause may suffice.
- In cases of chloride-responsive alkalosis, normal saline infusion and potassium chloride supplementation are key.
- For severe cases (pH >7.60), acetazolamide may be considered to enhance bicarbonate excretion.
- Chloride-resistant alkalosis requires specific treatment of the underlying condition, such as Cushing's syndrome or primary hyperaldosteronism.
- Discontinuation of loop diuretics and management of conditions causing excessive vomiting are crucial steps.
Underlying Conditions and Treatment
The management of metabolic alkalosis also involves understanding its pathophysiology, including the role of aldosterone in conditions like Bartter syndrome, as discussed in the context of K-sparing diuretics, angiotensin-converting enzyme inhibitors, and angiotensin receptor blockers [ 1 ]. However, the primary focus in treating metabolic alkalosis remains the correction of the underlying cause and the restoration of normal acid-base balance through the judicious use of fluids, electrolytes, and specific medications.
From the Research
Causes of Metabolic Alkalosis
- Metabolic alkalosis is a primary pathophysiologic event characterized by the gain of bicarbonate or the loss of nonvolatile acid from extracellular fluid 2
- The loss of acid may be via the gastrointestinal tract or via the kidney, whereas the sources of excess alkali may be via oral or parenteral alkali intake 2, 3
- Factors that help maintain metabolic alkalosis include decreased glomerular filtration rate, volume contraction, hypokalemia, hypochloremia, and aldosterone excess 2, 4
- Clinical states associated with metabolic alkalosis are vomiting, mineralocorticoid excess, the adrenogenital syndrome, licorice ingestion, diuretic administration, and Bartter's and Gitelman's syndromes 2, 3
Treatment Options for Metabolic Alkalosis
- Conventional conservative treatment of metabolic alkalosis involves meeting the patient's fluid and electrolyte needs and allowing the body to correct the alkalosis through its own mechanisms 5
- When more rapid resolution of the alkalosis is needed or the patient cannot tolerate fluid and electrolyte therapy, mineral acids may be administered 5
- Ammonium chloride and arginine monohydrochloride infusions may both be used; since both require hepatic conversion for full activity, patients with hepatic dysfunction may require alternative therapy 5
- Dilute hydrochloric acid (0.1-0.2 N) may be given intravenously to these patients through a central-venous catheter 5
- Acetazolamide, a carbonic anhydrase inhibitor, can be used to treat metabolic alkalosis by decreasing the serum strong ion difference 6
- The cornerstone of treatment is the correction of existing depletions and the prevention of further losses, such as infusion of potassium chloride to restore the excretion of bicarbonate by the kidney 4